Mixing devices of the aforementioned type are known for example from DE-PS 31 11 124 and EP-B-365 814. In the case of the first publication this mixing device is a so-called centrifugal mixer for dry materials and pastes, in which a mixing vessel is provided which is generally stationary and is open towards the top or closed off by a cover, and in which a mixing tool in the form of mixing blades which can be driven in rotation is provided immediately above the base of the container, the said mixing tool being driven by a drive shaft which is brought up vertically from below.
In the case of EP-B-365 814 the mixing device has a mixing vessel composed of two mixing vessel parts which can be separated from one another, of which a first mixing vessel part is transportable whilst a second mixing vessel part is held so as to be pivotable about a horizontal axis and has mixing tools which can be driven in rotation by the end of a drive shaft which protrudes into the mixing vessel through the base of this vessel part. In a starting position with a common vertical vessel axis the two mixing vessel parts can be clamped together to form one single mixing vessel and can then be pivoted about a horizontal axis by approximately 180.degree. into a mixing position in which the second vessel part forms the base part of the mixing vessel.
Powders, granulates, pigments, pastes, liquids or the like can be mixed with these known mixing devices. In practice, however, the mixing operation is frequently used for mixing different colours, qualities and the like. This necessitates careful cleaning of the mixing device, i.e. particularly the interior of the mixing vessel and the mixing tool operating therein, for example in the case of a colour change or a change in the product quality. In order to carry out this cleaning work the mixing tool is generally removed, which particularly in the case of larger mixing devices means that corresponding lifting equipment must be used, for example cranes, fork-lift trucks etc., which is extremely costly and awkward.
The object of the invention, therefore, is to improve a mixing device in such a way that using simple means a rapid and reliable cleaning of the inside of the mixing vessel and of the mixing tool is made possible.